Dr. Tracy is a Clinical Assistant Professor in the Division of Pediatric Pulmonary. His clinical interests include care for children with bronchopulmonary dysplasia (BPD), chronic respiratory failure, mechanical ventilation, childhood interstitial lung disease, and cystic fibrosis. He serves as the director of the BPD Clinic, and co-director of the Cardiac and Respiratory care for Infants with BPD (CRIB) Program. He is the physician lead for the inpatient Pulmonary consult service at LPCH. Dr. Tracy is currently involved clinical and translational research projects in the area of BPD and cystic fibrosis. With regard to medical education, he was formerly a chief resident in pediatrics at LPCH, and currently serves as a faculty coach in the pediatric residency program.

Clinical Focus

  • Pediatric Pulmonary
  • Bronchopulmonary Dysplasia
  • Cystic Fibrosis
  • Chronic Respiratory Failure / Mechanical Ventilation
  • Childhood Interstitial Lung Disease
  • Primary Ciliary Dyskinesia
  • Asthma

Academic Appointments

Administrative Appointments

  • Faculty Coach, Pediatric Residency Program (2018 - Present)
  • Chief Resident, Pediatric Residency Program (2011 - 2012)

Boards, Advisory Committees, Professional Organizations

  • Member, American Thoracic Society (2013 - Present)

Professional Education

  • Fellowship: Stanford University Pediatric Pulmonary Fellowship (2016) CA
  • Residency: Stanford University Pediatric Residency (2011) CA
  • Board Certification: American Board of Pediatrics, Pediatric Pulmonary (2016)
  • Board Certification: American Board of Pediatrics, Pediatrics (2011)
  • Medical Education: Warren Alpert Medical School Brown University (2008) RI

All Publications

  • Characteristics of infants or children presenting to outpatient bronchopulmonary dysplasia clinics in the United States. Pediatric pulmonology Collaco, J. M., Agarwal, A., Austin, E. D., Hayden, L. P., Lai, K., Levin, J., Manimtim, W. M., Moore, P. E., Sheils, C. A., Tracy, M. C., Alexiou, S., Baker, C. D., Cristea, A. I., Fierro, J. L., Rhein, L. M., Villafranco, N., Nelin, L. D., McGrath-Morrow, S. A. 2021


    INTRODUCTION: Bronchopulmonary dysplasia (BPD) is a common respiratory sequelae of preterm birth, for which longitudinal outpatient data are limited. Our objective was to describe a geographically diverse outpatient cohort of former preterm infants followed in BPD-disease specific clinics.METHODS: Seven BPD specialty clinics contributed data using standardized instruments to this retrospective cohort study. Inclusion criteria included preterm birth (<37 weeks) and respiratory symptoms or needs requiring outpatient follow-up.RESULTS: A total of 413 preterm infants and children were recruited (mean age: 2.4±2.7 years) with a mean gestational age of 27.0±2.8 weeks and a mean birthweight of 951±429 grams of whom 63.7% had severe BPD. Total, 51.1% of subjects were nonwhite. Severe BPD was not associated with greater utilization of acute care/therapies compared to non-severe counterparts. Of children with severe BPD, differences in percentage of those on any home respiratory support (p=.001), home positive pressure ventilation (p=.003), diuretics (p<.001), inhaled corticosteroids (p<.001), and pulmonary vasodilators (p<.001) were found between centers, however no differences in acute care use were observed.DISCUSSION: This examination of a multicenter collaborative registry of children born prematurely with respiratory disease demonstrates a diversity of management strategies among geographically distinct tertiary care BPD centers in the United States. This study reveals that the majority of children followed in these clinics were nonwhite and that neither variation in management nor severity of BPD at 36 weeks influenced outpatient acute care utilization. These findings suggest that post-neonatal intensive care unit factors and follow-up may modify respiratory outcomes in BPD, possibly independently of severity.

    View details for DOI 10.1002/ppul.25332

    View details for PubMedID 33713587

  • Bronchopulmonary Dysplasia: Then, Now, and Next Pediatric Allergy, Immunology, and Pulmonology Tracy, M. C., Cornfield, D. N. 2020; 33 (3): 99-109

    View details for DOI 10.1089/ped.2020.1205

  • Three Infants with Pathogenic Variants in the ABCA3 Gene: Presentation, Treatment and Clinical Course. The Journal of pediatrics Si, n. n., X, n. n., Steffes, n. n., L C, n. n., Schymick, n. n., J C, n. n., Hazard, n. n., F K, n. n., Tracy, n. n., M C, n. n., Cornfield, n. n., D N, n. n. 2020

    View details for DOI 10.1016/j.jpeds.2020.12.055

    View details for PubMedID 33359301

  • Characteristics of Infants/Children Presenting to Outpatient Bronchopulmonary Dysplasia Clinics in the United States Collaco, J. M., Hayden, L. P., Agarwal, A., Alexiou, S., Austin, E. D., Baker, C. D., Cristea, A., DeMauro, S. B., Fierro, J. L., Lai, K., Levin, J. C., Manimtim, W. M., Moore, P. E., Rhein, L. M., Sheils, C. A., Tracy, M. C., McGrath-Morrow, S. A. AMER THORACIC SOC. 2020
  • Methods for Extraction and Detection of Pf Bacteriophage DNA from the Sputum of Patients with Cystic Fibrosis. PHAGE (New Rochelle, N.Y.) Burgener, E. B., Secor, P. R., Tracy, M. C., Sweere, J. M., Bik, E. M., Milla, C. E., Bollyky, P. L. 2020; 1 (2): 100–108


    Background: There is increasing interest in the pulmonary microbiome's bacterial and viral communities, particularly in the context of chronic airway infections in cystic fibrosis (CF). However, the isolation of microbial DNA from the sputum from patients with CF is technically challenging and the optimal protocols for the analysis of viral species, including bacteriophage, from clinical samples remains difficult. Materials and Methods: In this study, we evaluate a set of methods developed for processing and analyzing sputum from patients with CF with the goal of detecting Pf bacteriophage virion-derived nucleic acid. We evaluate the impact of bead beating, deoxyribonuclease digestion, and heating steps in these protocols focusing on the quantitative assessment of Pseudomonas aeruginosa and Pf bacteriophage in sputum. Results: Based on these comparative data, we describe an optimized protocol for processing sputum from patients with CF and isolating DNA for polymerase chain reaction or sequencing-based studies. Conclusion: These studies demonstrate the assessment of a specific bacteriophage and bacteria in sputum from patients with CF.

    View details for DOI 10.1089/phage.2020.0003

    View details for PubMedID 32626852

    View details for PubMedCentralID PMC7327540

  • Not All ABCA3 Mutations Are Created Equal Si, X., Tracy, M. AMER THORACIC SOC. 2019
  • More than BPD? Diagnosis, Prognosis and Treatment of ABCA3 Deficiency in an Extremely Premature Infant Steffes, L. C., Tracy, M., Cornfield, D. N. AMER THORACIC SOC. 2019
  • The myriad challenges of respiratory fungal infection in cystic fibrosis PEDIATRIC PULMONOLOGY Tracy, M. C., Moss, R. B. 2018; 53: S75–S85

    View details for DOI 10.1002/ppul.24126

    View details for Web of Science ID 000446457700006

  • The myriad challenges of respiratory fungal infection in cystic fibrosis. Pediatric pulmonology Tracy, M. C., Moss, R. B. 2018


    Fungal infection in cystic fibrosis (CF) is a recognized challenge, with many areas requiring further investigation. Consensus definitions exist for allergic bronchopulmonary aspergillus in CF, but the full scope of clinically relevant non-allergic fungal disease in CF-asymptomatic colonization, transient or chronic infection localized to endobronchial mucus plugs or airway tissue, and invasive disease-is yet to be clearly defined. Recent advances in mycological culture and non-culture identification have expanded the list of both potential pathogens and community commensals in the lower respiratory tract. Here we aim to outline the current understanding of fungal presence in the CF respiratory tract, risk factors for acquiring fungi, host-pathogen interactions that influence the role of fungi from bystander to pathogen, advances in the diagnostic approaches to isolating and identifying fungi in CF respiratory samples, challenges of classifying clinical phenotypes of CF patients with fungi, and current treatment approaches. Development and validation of biomarkers characteristic of different fungal clinical phenotypes, and controlled trials of antifungal agents in well-characterized target populations, remain central challenges to surmount and goals to be achieved.

    View details for PubMedID 29992775

  • Complicated pneumonia: current concepts and state of the art. Current opinion in pediatrics Tracy, M. C., Mathew, R. n. 2018


    This review aims to provide clinicians engaged in the care of infants and children an update on the current understanding of the epidemiology, etiology, diagnostic evaluation, and clinical management of complicated pneumonia. The review provides timely information surrounding areas of consensus and ongoing research.The epidemiology and etiologies of complicated pneumonia continue to evolve over the past several decades in context of the introduction of new vaccines. We review uncommon and emerging pathogens. Immunocompromised patients are particularly at risk for complications. The 2011 clinical practice guidelines for pediatric community-acquired pneumonia from The Pediatric Infectious Diseases Society/Infectious Diseases Society of America and the British Thoracic Society are changing approaches to evaluation and management. The efficacy of new diagnostic laboratory studies, and imaging techniques, continues to be studied. Antibiotics are the mainstay of treatment, with several new options to consider. Techniques for the drainage of parapneumonic effusions continue to optimize.Although much is known about complicated pneumonia, it remains a significant burden. New diagnostic and therapeutic interventions hold much promise. This review seeks to provide clinicians with evidence that motivates a reasoned approach to the evaluation and management of complicated pneumonia.

    View details for PubMedID 29528891

  • Un-Even Steven: An Unusual Complication of Stevens-Johnson Syndrome Hamberger, E., Tracy, M. AMER THORACIC SOC. 2018
  • The evolution of disease: chronic lung disease of infancy and pulmonary hypertension CURRENT OPINION IN PEDIATRICS Tracy, M. C., Cornfield, D. N. 2017; 29 (3): 320-325


    Bronchopulmonary dysplasia (BPD) or chronic lung disease of infancy BPD was originally described 50 years ago, in 1967 by Northway et al. This article possesses two fundamental objectives to provide: a brief historical perspective on BPD; and an update relative to current notions of epidemiology, pathophysiology, evaluation, and clinical management of BPD complicated by vascular disease. The review highlights areas of consensus and ongoing uncertainty.The clinical cause and presentation of infants with BPD has evolved over the past several decades. Considerable improvements in neonatal care, including surfactant replacement therapies, antenatal steroids, nutritional support, ventilator management, and attention to the potential of oxygen toxicity, underlie the evolution of BPD. Most children with BPD improve over time. However, in the presence of vascular disease, the morbidity and mortality associated with BPD increases considerably. Though recent recommendations include procuring an echocardiogram to screen for pulmonary hypertension in infants with established BPD, there is less agreement surrounding the additional diagnostic and putative treatment modalities for infants with BPD and pulmonary hypertension. The indications, rationale, potential benefits, and risks of vasodilator therapy in BPD are discussed.The pediatric community has 50 years of experience with BPD. Past experience should be used to inform present and future diagnostic and treatment strategies. This review seeks to arm the clinician with evidence that motivates a physiology-based approach to the management of infants with BPD and pulmonary hypertension.

    View details for DOI 10.1097/MOP.0000000000000490

    View details for Web of Science ID 000401074000011

    View details for PubMedID 28338487

  • Bronchoscopy in children with tetralogy of fallot, pulmonary atresia, and major aortopulmonary collaterals. Pediatric pulmonology Sidell, D. R., Koth, A. M., Bauser-Heaton, H., McElhinney, D. B., Wise-Faberowski, L., Tracy, M. C., Hanley, F. L., Asija, R. 2017


    Children with Tetralogy of Fallot, Pulmonary Atresia, and Major Aortopulmonary Collaterals (TOF/PA/MAPCAs) undergoing unifocalization surgery are at risk for developing more postoperative respiratory complications than children undergoing other types of congenital heart surgery. Bronchoscopy is used in the perioperative period for diagnostic and therapeutic purposes. In this study, we describe bronchoscopic findings and identify factors associated with selection for bronchoscopy.Retrospective case-control.All patients with TOF/PA/MAPCAs who underwent unifocalization surgery from September 2005 through March 2016 were included. Patients who underwent bronchoscopy in the perioperative period were compared to a randomly selected cohort of 172 control patients who underwent unifocalization without bronchoscopy during the study period.Forty-three children underwent perioperative bronchoscopy at a median of 9 days postoperatively. Baseline demographics were similar in bronchoscopy patients and controls. Patients who underwent bronchoscopy were more likely to have a chromosome 22q11 deletion and were more likely have undergone unifocalization surgery without intracardiac repair. These patients had a longer duration of mechanical ventilation, ICU duration, and length of hospitalization. Abnormalities were detected on bronchoscopy in 35 patients (81%), and 20 (35%) of bronchoscopy patients underwent a postoperative intervention related to abnormalities identified on bronchoscopy.Bronchoscopy is a useful therapeutic and diagnostic instrument for children undergoing unifocalization surgery, capable of identifying abnormalities leading to an additional intervention in over one third of patients. Special attention should be given to children with a 22q11 deletion to expedite diagnosis and intervention for possible airway complications.

    View details for DOI 10.1002/ppul.23732

    View details for PubMedID 28504356

  • Children With Bronchiolitis on High-Flow Nasal Cannula: To Feed or Not Feed, That Is Not the Only Question. Hospital Pediatrics Tracy, M. C., Cornfield, D. N. 2017; 7 (5): 297-299

    View details for DOI 10.1542/hpeds.2017-0047

  • Allergic Bronchopulmonary Aspergillosis Journal of Fungi Tracy, M. C., Okorie, C. A., Foley, E. A., Moss, R. B. 2016; 2 (2): 17

    View details for DOI 10.3390/jof2020017

  • Respiratory Microbiology In Primary Ciliary Dyskinesia: Comparisons To A Pediatric Cystic Fibrosis Cohort Tracy, M. C., Zirbes, J. M., Hernandez, C., Cornfield, D. N., Milla, C. E. AMER THORACIC SOC. 2016
  • Dna Extraction From Cystic Fibrosis Sputum Samples Is Not Method Dependent Tracy, M. C., Yacob, A., Chen, C., Milla, C. E., Cornfield, D. N. AMER THORACIC SOC. 2016
  • Allergic Bronchopulmonary Aspergillosis. Journal of fungi (Basel, Switzerland) Tracy, M. C., Okorie, C. U., Foley, E. A., Moss, R. B. 2016; 2 (2)


    Allergic bronchopulmonary aspergillosis (ABPA), a progressive fungal allergic lung disease, is a common complication of asthma or cystic fibrosis. Although ABPA has been recognized since the 1950s, recent research has underscored the importance of Th2 immune deviation and granulocyte activation in its pathogenesis. There is also strong evidence of widespread under-diagnosis due to the complexity and lack of standardization of diagnostic criteria. Treatment has long focused on downregulation of the inflammatory response with prolonged courses of oral glucocorticosteroids, but more recently concerns with steroid toxicity and availability of new treatment modalities has led to trials of oral azoles, inhaled amphotericin, pulse intravenous steroids, and subcutaneously-injected anti-IgE monoclonal antibody omalizumab, all of which show evidence of efficacy and reduced toxicity.

    View details for PubMedID 29376934

  • Invasive Pulmonary Aspergillosis As The Presenting Sign In A Child With Systemic Lupus Erythematosus Tracy, M. C., Mark, J. D., Cornfield, D. N. AMER THORACIC SOC. 2016
  • The pediatric microbiome and the lung CURRENT OPINION IN PEDIATRICS Tracy, M., Cogen, J., Hoffman, L. R. 2015; 27 (3): 348-355


    Many pediatric lung diseases are characterized by infection. These infections are generally diagnosed, studied, and treated using standard culture methods to identify 'traditional pathogens'. Based on these techniques, healthy lungs have generally been thought to be sterile. However, recent advances in culture-independent microbiological techniques challenged this paradigm by identifying diverse microbes in respiratory specimens (respiratory microbiomes) from both healthy people and those with diverse lung diseases. In addition, growing evidence suggests a link between gastrointestinal microbiomes and inflammatory diseases of various mucosal surfaces, including airways.This article reviews the rapidly developing field of respiratory microbiome research, emphasizing recent progress made employing increasingly sophisticated technologies. Although many of the relevant studies have focused on adults with cystic fibrosis, recent research has included children and adults with other respiratory diseases, as well as healthy individuals. These studies suggest that even healthy children have airway microbiomes, and that both respiratory and gastrointestinal microbiomes often differ between healthy people and those with different types and severities of airway disease. The causal relationships between microbiomes, disease type and progression, and treatments such as antibiotics must now be defined.The advent of culture-independent microbiological techniques has transformed how we think about the relationship between microbes and airway disease. More research is required to translate these findings to improved therapies and preventive strategies.

    View details for DOI 10.1097/MOP.0000000000000212

    View details for Web of Science ID 000354214800014

    View details for PubMedID 25888147

    View details for PubMedCentralID PMC4443818

  • Pulmonary Hemorrhage In An Adolescent Using Inhaled Illicit Drugs: Not Just Blowing Smoke Tracy, M. C., Mark, J. D. AMER THORACIC SOC. 2015
  • Chest Pain, Dyspnea On Exertion, And Severe Exercise Intolerance: Evaluation And Diagnosis In An Adolescent With Multiple Medical Comorbidities Tracy, M. C., Rogers, I. S., Maeda, K., Mitchell, R., Tremmel, J., Schnittger, I., Robinson, T. E. AMER THORACIC SOC. 2014